Multi-platinum pop princess Taylor Swift may have invaded concert-goers’ privacy in an effort to identify stalkers at her May 18 performance in Los Angeles.

The facial recognition system was built into a kiosk playing rehearsal footage for Swift’s “Reputation” tour. Attendees would stop to view the footage, and a hidden camera would record their faces, sending the images to a “command post” in Nashville. There, they would be cross-referenced with a database of the hundreds of stalkers who have pursued Swift in the past.

“Everybody who went by would stop and stare at it, and the software would start working,” said Oak View Group chief security officer Mike Downing. Downing is one of the many people tasked with keeping entertainers safe at Madison Square Garden, and the LA venue where Swift gave her Rose Bowl performance. Downing was invited to the show by the manufacturers of the scanning technology used.

According to The Guardian, because the venues are considered private, it is perfectly legal to record fans without notice. Those uncomfortable with such practices will have to catch Reputation when it debuts on Netflix on the last day of 2018.

Meanwhile, two prominent Taylor Swift stalkers face the consequences of their behavior. Julius Sandrock was “wearing a mask and had a knife in his car, and told police that he had driven from Colorado to visit the singer.”

Soon after, another stalker by the name of Mohammed Jaffar earned six months in jail and five years of probation for burglary. He appeared at Swift’s home five times in just two months. Swift has numerous restraining orders filed against the most aggressive “fans.”